A memory device having a three-dimensional structure has been proposed in which a memory hole is made in a stacked body in which multiple electrode layers are stacked, and a charge storage film and a semiconductor film are provided to extend in a stacking direction of the stacked body inside the memory hole. The memory device includes multiple memory cells connected in series between a drain-side select transistor and a source-side select transistor. A drain of the memory cell is electrically connected to a bit line via the drain-side select transistor. A source of the memory cell is electrically connected to a source line via the source-side select transistor. In general, a slit is formed in the stacked body, and the source line is provided in the slit. However, when the source line is provided in the slit, a width of the slit widens. Therefore, a reduction in a planar size of a memory cell array is obstructed. It is desirable to reduce in the planar size of the memory cell array.